Robotic surgical instrument and methods using bragg fiber sensors

ABSTRACT

A positionable medical instrument assembly, e.g., a robotic instrument driver configured to maneuver an elongate medical instrument, includes a first member coupled to a second member by a movable joint, with a Bragg fiber sensor coupled to the first and second members, such that relative movement of the first and second members about the movable joint causes a bending of at least a portion of the Bragg fiber sensor. The Bragg fiber sensor has a proximal end operatively coupled to a controller configured to receive signals from the Bragg fiber sensor indicative of a bending thereof, the controller configured to analyze the signals to determine a relative position of the first and second members about the movable joint.

RELATED APPLICATION DATA

The present application claims the benefit under 35 U.S.C. § 119 to U.S. Provisional Patent Application Ser. Nos. 60/899,048, filed on Feb. 2, 2007, and 60/900,584, filed on Feb. 8, 2007. The foregoing applications are hereby incorporated by reference into the present application in its entirety.

FIELD OF INVENTION

The invention relates generally to medical instruments having multiple jointed devices, including for example telerobotic surgical systems, and more particularly to a method, system, and apparatus for sensing or measuring the position, temperature and/or stress and strain at one or more positions along the multiple jointed device.

BACKGROUND

Robotic interventional systems and devices are well suited for use in performing minimally invasive medical procedures, as opposed to conventional techniques wherein the patient's body cavity is open to permit the surgeon's hands access to internal organs. For example, there is a need for a highly controllable yet minimally sized system to facilitate imaging, diagnosis, and treatment of tissues which may lie deep within a patient, and which may be accessed via naturally-occurring pathways such as blood vessels, other lumens, via surgically-created wounds of minimized size, or combinations thereof.

SUMMARY OF THE INVENTION

In one embodiment, a positionable medical instrument assembly, e.g., a robotic instrument driver configured to maneuver an elongate medical instrument, includes a first member coupled to a second member by a movable joint, with a Bragg fiber sensor coupled to the first and second members, such that relative movement of the first and second members about the movable joint causes a bending of at least a portion of the Bragg fiber sensor. The Bragg fiber sensor has a proximal end operatively coupled to a controller configured to receive signals from the Bragg fiber sensor indicative of a bending thereof, the controller configured to analyze the signals to determine a relative position of the first and second members about the movable joint. By way of non-limiting example, the movable joint may allow for pivotal motion of the second member relative to the first member in a single plane, and wherein the determined relative position of the first and second members about the movable joint comprises an angular displacement of the second member relative to the first member. Alternatively, the movable joint may allow for movement of the second member relative to the first member in at least three degrees of freedom.

In another embodiment, a positionable medical instrument assembly includes a plurality of positionable members, including a first member coupled to a second member by a first movable joint, and a third member coupled to the second member by a second movable joint. One or more Bragg fiber sensors are provided, each coupled to at least two of the first, second and third members, such that relative movement of the first and second members about the first movable joint causes a corresponding bending of at least one Bragg fiber sensor, and a relative movement of the second and third members about the second movable joint causes a corresponding bending of at least one Bragg fiber sensor. Each of the one or more Bragg fiber sensors having a proximal end operatively coupled to a controller configured to receive signals therefrom indicative of a bending of one or more portions thereof, the controller configured to analyze the signals to determine a relative position of the first, second and third members about the respective first and second movable joints. By way of non-limiting examples, the first movable joint may allow for movement of the second member relative to the first member in at least three degrees of freedom, and the second movable joint may allow for movement of the third member relative to the second member in at least three degrees of freedom.

In one such embodiment, the one or more Brag fiber sensors include a first Bragg fiber sensor coupled to the first, second and third members, such that relative movement of the first and second members about the first movable joint, and relative movement of the second and third members about the second movable joint causes a bending of at least first and second respective portions of the first Bragg fiber sensor. In this embodiment, the controller is configured to analyze signals received from the first Bragg fiber sensor to determine a relative position of the first, second and third members about the respective first and second movable joints.

In another such embodiment, the one or more Brag fiber sensors include a first Bragg fiber sensor coupled to the first and second members, such that relative movement of the first and second members about the first movable joint causes a bending of at least a portion of the first Bragg fiber sensor, and a second Bragg fiber sensor coupled to the second and third members, such that relative movement of the second and third members about the second movable joint causes a bending of at least a portion of the second Bragg fiber sensor, wherein the controller is configured to analyze respective signals received from the first and second Bragg fiber sensors to determine a relative position of the first, second and third members about the respective first and second movable joints.

In yet another embodiment, a positionable medical instrument assembly includes a first member coupled to a second member by a movable joint, with a plurality of Bragg fiber sensors coupled to the first and second members, such that relative movement of the first and second members about the movable joint causes a bending of at least a portion of each of the plurality of the Bragg fiber sensors. The Bragg fiber sensors have respective proximal ends operatively coupled to a controller configured to receive signals from each of the Bragg fiber sensors indicative of a respective bending thereof. The controller is configured to analyze the signals to determine a relative position of the first and second members about the movable joint. By way of example, the movable joint may allow for pivotal motion of the second member relative to the first member in a single plane, wherein the determined relative position of the first and second members about the movable joint comprises an angular displacement of the second member relative to the first member. By way of another example, the movable joint may allow for movement of the second member relative to the first member in at least three degrees of freedom. In various embodiments, the assembly comprises a robotic instrument driver configured to maneuver an elongate medical instrument movably coupled to the second member.

In still another embodiment, a medical instrument system is provided, the system including an instrument driver, a sterile barrier, an elongate flexible instrument body operatively coupled to the instrument driver through the sterile barrier, and a Bragg fiber sensor coupled to the elongate instrument body, such that relative bending of the instrument body causes a corresponding bending of at least a portion of the Bragg fiber sensor. The Bragg fiber sensor has a proximal end operatively coupled to a position sensor controller located on a sterile field side of the sterile barrier and configured to receive signals from the Bragg fiber sensor indicative of a bending thereof, the sensor controller configured to analyze the signals to determine a relative position of the instrument. In one such embodiment, the position sensor controller transmits wireless signals to an instrument driver controller located outside the sterile field to communicate to the instrument driver a relative position of the instrument.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate the design and utility of illustrated embodiments of the invention, in which similar elements are referred to by common reference numerals.

FIG. 1 illustrates a conventional manually-steerable catheter;

FIG. 2 illustrates one embodiment of a robotically-driven steerable catheter;

FIGS. 3A-3C illustrate one embodiment of a robotically-steerable catheter having an optical fiber positioned along one aspect of the wall of the catheter;

FIG. 4 illustrates a cross sectional view of a portion of FIG. 3A;

FIG. 5 illustrates another embodiment wherein a composite fiber bundle is positioned within the wall of the catheter;

FIG. 6A illustrates a perspective view of a da Vinci telesurgical system including its operator control station and surgical work station;

FIG. 6B shows a perspective view of a cart of the telesurgical system carrying three robotically controlled manipulator arms, each have a Bragg fiber assembly mounted thereon;

FIG. 6C is a perspective view of a da Vinci robotic surgical arm cart system;

FIG. 6D is a side view of a robotic arm and surgical instrument assembly from a da Vinci system, the instrument assembly having a sensor cable connected to its Bragg fiber bundle;

FIG. 6E illustrates a surgical instrument of the da Vinci system;

FIG. 6F illustrates an exemplary operating room installation of a patient-side telesurgical system;

FIG. 6G-L illustrate various embodiments of fiber bragg sensors operably coupled to articulated robotic instrument configurations;

FIG. 7A illustrates a perspective view of a system for magnetically assisted surgery;

FIG. 7B illustrates a patient lying on the patient support and having a Stereotaxis magnetic catheter including a Bragg fiber introduced into the patient's head;

FIGS. 7C-7E illustrate various embodiments of magnetic ablation catheters having one or more Bragg fiber bundles;

FIG. 8A illustrates one embodiment of a Mako haptic guidance surgical system that utilizes method of position determination with a Bragg fiber;

FIG. 8B illustrates one embodiment of a Mako haptic robot;

FIG. 9A illustrates one embodiment of a radiosurgery system employing a Bragg fiber position sensing scheme;

FIG. 9B illustrates the distal portion of the Accuray robot arm to which the beaming apparatus is mounted;

FIG. 10A illustrates one embodiment of a steerable endoscope;

FIG. 10B illustrates a cross-sectional side view of a patient's head;

FIG. 10C illustrates a cross-sectional anterior view of a heart;

FIGS. 10D-10F show examples of a treating atrial fibrillation using an endoscopic device that includes a Bragg sensor fiber;

FIG. 10G illustrates an endoscope having a guide tube which is slidably insertable within the lumen of a guide tube;

FIG. 10H illustrates a colonoscopy procedure wherein a NeoGuide steerable endoscope with a Bragg sensor fiber is advanced through a colon;

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The present invention is directed to various interventional medical instruments, such as jointed positioning instruments, catheters and endoscopic devices, with Bragg fiberoptic grating guidance systems. Advantageously, each of the embodiments of the present invention described herein may be utilized with robotic catheter systems, which can control the positioning of the devices within a patients body, and may also control the operation of other functions of the devices, such as imaging devices, ablation devices, cutting tools, or other end effectors. The devices may be controlled using a closed-loop servo control in which an instrument is moved in response to a command, and then the determined position may be utilized to further adjust the position; or an open loop control in which an instrument is moved in response to a user command, the determined position is then displayed to the user, and the user can then input another command based on the displayed position.

In addition, by determining the strain or deflection of various portions of an instrument and utilizing kinematics and mechanics of materials relationships pertinent to the structures of the instrument, applied loads (preferably including magnitude and vector) may be estimated. In other words, by utilizing a kinematic model of an instrument fitted with one or more Bragg fiber sensor(s), and a mechanics model of how the instrument should deflect or strain under load, a comparison may be made between the expected position of the instrument, as determined utilizing the kinematic and/or mechanics relationships, and the actual position of the instrument, determined utilizing the Bragg fiber sensor data. The difference between actual and expected may then be analyzed utilizing the kinematic and/or mechanics relationships to determine what kind of load must have been applied to cause the difference between actual and expected—and thereby the load may be characterized. For example, taking a two-link instrument wherein the distal link is basically a flexible polymeric cylinder; a kinematic model can be used to predict how the cylinder should move relative to the more proximal pieces when actuated, and it should retain its original shape unless it is subjected to an external load; if the Bragg fiber sensor data indicates that the cylinder is bending, then the applied load can be calculated (e.g. a formula relating the bending to the load can be determined, or a lookup table of predetermined empirical data could be used). Thus, by using the Bragg fiber sensor to measure deflections or strains in different parts of the instrument, forces on the instrument and stresses within the instrument may be determined.

Examples of robotic catheter systems and their components and functions have been previously described in the following U.S. patent applications, which are incorporated herein by reference in their entirety: U.S. patent application Ser. Nos. 10/923,660, filed Aug. 20, 2004; 10/949,032, filed Sep. 24, 2005; 11/073,363, filed Mar. 4, 2005; 11/173,812, filed Jul. 1, 2005; 11/176,954, filed Jul. 6, 2005; 11/179,007, filed Jul. 6, 2005; 11/202,925, filed Aug. 12, 2005; 11/331,576, filed Jan. 13, 2006; 60/785,001, filed Mar. 22, 2006; 60/788,176, filed Mar. 31, 2006; 11/418,398, filed May 3, 2006; 11/481,433, filed Jul. 3, 2006; 11/637,951, filed Dec. 11, 2006; 11/640,099, filed Dec. 14, 2006; 60/833,624, filed Jul. 26, 2006 and 60/835,592, filed Aug. 3, 2006.

All of the following technologies may be utilized with manually or robotically steerable instruments, such as those described in the aforementioned patent application, U.S. Ser. No. 11/481,433. In addition, all of the following technologies may be utilized with the robotic catheter systems and methods described in the U.S. patent applications listed above, and incorporated by reference herein.

For clarity, the sheath and guide catheter instruments described in the exemplary embodiments below may be described as having a single lumen/tool/end-effector, etc. However, it is contemplated that alternative embodiments of catheter instruments may have a plurality of lumens/tools/end-effectors/ports, etc. Furthermore, it is contemplated that in some embodiments, multiple catheter instruments may be delivered to a surgical site via a single multi-lumen sheath, each of which is robotically driven and controlled via an instrument driver. Some of the catheter instruments described herein are noted as flexible. It is contemplated that different embodiments of flexible catheters may be designed to have varying degrees of flexibility and control. For example, one catheter embodiment may have controlled flexibility throughout its entire length whereas another embodiment may have little or no flexibility in a first portion and controlled flexibility in a second portion. Similarly, different embodiments of these catheters may be implemented with varying degrees of freedom.

With reference to the figures, the implementation of fiberoptic Bragg grating sensing to various interventional medical devices will be described. Fiberoptic Bragg grating sensing can be implemented onto interventional medical devices to determine the location of various parts of the device by positioning the fiberoptic bundle longitudinally along the device and calculating the deflection of the fiberoptic bundle. The determination of the deflections of portions of a Fiberoptic Bragg grating sensor is known in the relevant art, but the integration of strains or deflections associated with various portions of a multi-part or articulated medical instrument utilizing one or more Fiberoptic Bragg grating sensors to predict the position of multi-part medical instrument in space.

Referring to FIG. 1, a conventional manually-steerable catheter (1) is depicted. A plurality of pullwires (2) may be selectively tensioned through manipulation of a handle (3) on the proximal portion of the catheter structure (1) to make a more flexible distal portion (5) of the catheter bend or steer controllably. A more proximal and conventionally less steerable portion (4) of the catheter may be configured to be compliant to loads from surrounding tissues (for example, to facilitate passing the catheter, including portions of the proximal portion, through tortuous pathways such as those formed by the blood vessels), yet less steerable as compared with the distal portion (5).

Referring to FIG. 2, a robotically-driven steerable catheter (6), similar to those described in detail in U.S. patent application Ser. No. 11/176,598, incorporated by reference herein in its entirety, is depicted. This catheter (6) has some similarities with the manually-steerable catheter (1) of FIG. 1 in that it has pullwires (10) associated distally with a more flexible section (8) configured to steer or bend when the pullwires (10) are tensioned in various configurations, as compared with a less steerable proximal portion (7) configured to be stiffer and more resistant to bending or steering. The depicted embodiment of the robotically-driven steerable catheter (6) comprises proximal axles or spindles (9) configured to primarily interface not with fingers or the hand, but with an electromechanical instrument driver configured to coordinate and drive, with the help of a computer, each of the spindles (9) to produce precise steering or bending movement of the catheter (6). For example, the spindles (9) may be the same or similar to the control element interface assemblies which can be controlled by an instrument drive assembly as shown and described in U.S. patent application Ser. No. 11/637,951.

Each of the embodiments depicted in FIGS. 1 and 2 may have a working lumen (not shown) located, for example, down the central axis of the catheter body, or may be without such a working lumen. If a working lumen is formed by the catheter structure, it may extend directly out the distal end of the catheter, or may be capped or blocked by the distal tip of the catheter. It is highly useful in many procedures to have precise information regarding the spatial position of the distal portion or tip of elongate instruments, such as the instruments available from suppliers such as the Ethicon Endosurgery division of Johnson & Johnson, or Intuitive Surgical Corporation, during diagnostic or interventional procedures. The examples and illustrations that follow are made in reference to a robotically-steerable catheter such as that depicted in FIG. 2, but as would be apparent to one skilled in the art, the same principles may be applied to other elongate instruments, such as the manually-steerable catheter depicted in FIG. 1, or other elongate instruments, flexible or not, from suppliers such as the Ethicon Endosurgery division of Johnson & Johnson, Inc., or Intuitive Surgical, Inc.

Referring to FIGS. 3A-3C, a robotically-steerable catheter (6) is depicted having an optical fiber (12) positioned along one aspect of the wall of the catheter (6). The fiber is not positioned coaxially with the neutral axis of bending (11) in the bending scenarios depicted in FIGS. 3B and 3C. Indeed, with the fiber (12) attached to, or longitudinally constrained by, at least two different points along the length of the catheter (6) body and unloaded from a tensile perspective relative to the catheter body in a neutral position of the catheter body such as that depicted in FIG. 3A, the longitudinally constrained portion of the fiber (12) would be placed in tension when the catheter (6) is deflected as depicted in FIG. 3B, while the longitudinally constrained portion of the fiber (12) would be placed in compression when the catheter (6) is deflected as depicted in FIG. 3C. Such relationships are elementary to solid mechanics, but may be applied as described herein with the use of a Bragg fiber grating to assist in the determination of temperature and/or deflection of an elongate instrument. Examples of fiberoptic Bragg fiber sensing technology may be available from Luna Innovations, Inc. of Roanoke, Va., Micron Optics, Inc., of Atlanta, Ga., LxSix Photonics, Inc., of Quebec, Canada, and Ibsen Photonics A/S, of Denmark.

Referring to FIG. 4, a cross section of a portion of the configuration depicted in FIG. 3A is depicted, to clearly illustrate that the fiber (12) is not placed concentrically with the neutral axis (11) of bending for the sample cross section. FIG. 5 depicts a different variation, wherein a composite fiber bundle (13) is positioned within the wall of the catheter rather than a single fiber as depicted in FIG. 4. The fiber bundle (13) comprises three smaller single fibers (14). When a structure such as that depicted in FIG. 5 is placed in bending in a configuration such as that depicted in FIG. 3B or 3C, the most radially outward (from the neutral axis of bending (11)) of the three single fibers (14) experiences more compression or tension than the two more radially inward fibers. Thus, as explained above, a Bragg sensing fiber assembly may comprise a single fiber or multiple fibers, and the term Bragg sensing fiber, Bragg fiber sensor, or Bragg sensing fiber (16, 220, or 222) (when used in a drawing figure) as used herein shall mean any Bragg sensing fiber assembly having one or more fibers, unless the number of fibers is explicitly specified.

It is contemplated that various medical systems for minimally invasive surgery may utilize alternative embodiments of catheters including fiberoptic Bragg grating fibers and associated sensors for measuring strain and determining positions along an elongated instrument similar to those described in detail in U.S. Provisional Patent Applications Nos. 60/785,001 (filed Mar. 22, 2006) and 60/788,176 (filed Mar. 31, 2006), both incorporated by reference herein in their entirety.

For example, one or more Bragg sensing fibers may be included with each of the arms of a “da Vinci Surgical System” available from Intuitive Surgical Inc. of Sunnyvale, Calif. FIG. 6A illustrates a perspective view of a da Vinci telesurgical system (20) including its operator control station (22) and surgical workstation (24). The surgical workstation (24) comprises a cart (26), which supports the robotic arms (28). A Bragg fiber sensor (16) is disposed along at least a portion of the length of each arm (28). Alternatively, multiple separate Bragg fiber sensors (16) may be disposed on each arm (28). For example, a separate Bragg fiber sensor (16) may be disposed on each link of the robotic arm (28). In the depicted embodiments, Bragg fiber sensors (16) may be operably coupled to interventional and/or diagnostic instruments, such as the depicted robotic arm (28), utilizing bands, clips, fasteners, a layer of at least partically encapsulating material, or the like, distributed along the length of the robotic arm or other structure to maintain the position of the fiber sensor (16) relative to the position of the pertinent portions of such structure. Referring again to FIG. 6A, a position determining system (30) is depicted operatively coupled to each of the Bragg fiber sensors (16). The position determining system (30), generally comprising an optical radiation emitter and detector, and a computing system to analyze detected optical radiation, may be operatively coupled to each of the Bragg fiber sensors (16) via the cart (26). The position determining system (30) is configured to analyze data from the Bragg fiber sensors (16) as the arms (28) are maneuvered and determine changes in elongation of the Bragg fiber sensors (16). Some systems, such as those available from Luna Innovations, Inc., may be configured to utilize sensed deflection data to determine the spatial positioning or shape of a particular fiber or bundle of fibers. Although it is referred to herein as a “position determining system,” such system may also analyze, calculate and/or determine other information using the data from the Bragg fiber sensors, including without limitation, stress, strain or elongation, forces, and/or temperature. The positioning determining system (30) is also operatively coupled to the operator control station (22) or control system of the instrument system, such that position information as determined by the position determining system (30) may be relayed to the operator control system (22) to assist in navigation and control of the instrument system. In this illustration, the surgical workstation (24) carries three robotically controlled arms (28), and the movement of the arms (28) is remotely controllable from the control station (22). In other embodiments, the cart (26) may carry a varying number of arms (28) (i.e., two or four arms) depending on the particular configuration.

It is desirable to minimize (or even eliminate) the need to pass instruments through sterile barrier (or drape). Thus, the devices located on one side of the sterile barrier may use a wireless communication link to communicate with devices located on the other side of the sterile barrier. To this end, the position determining system may be configured to be placed within the sterile barrier and communicate wirelessly with the control station. Alternatively, as depicted in FIG. 6K, a sensing system subportion (226) may be positioned on the sterile side of the sterile barrier (214) and configured to wirelessly communicate with a wirelessly-enabled fiber Bragg sensing system (30)—to avoid having fibers physically crossing the sterile barrier (214). The position determining system (30) may then communicate with other components of the system via the wireless communication link, using RF, infrared or other suitable communications technologies, eliminating the need to pass a wires back and forth, or across the sterile barrier.

FIG. 6B shows a perspective view of the cart (26) of the telesurgical system carrying three robotically controlled manipulator arms (28), each having a Bragg fiber sensor (16) disposed thereon, and extending along the catheters (32) operatively coupled to the arms (28). For one embodiment, the fiber sensors (16) may be routed through the support structure of the arms (28) to the catheters (32). In another embodiment, the fiber sensors (16) may be freely connected from the position determining system (30) directly to each of the catheter assemblies (32).

FIG. 6C is a perspective view of another embodiment of a da Vinci robotic surgical arm cart system (40) in which a series of passive set-up joints (42) support robotically actuated manipulator arms (28) (typically, the center arm would support a camera). In this illustration, a wireless Bragg fiber relay (46) is attached to each of the catheter assemblies (32) mounted on the manipulator arms (44). Each wireless Bragg fiber relay (46) is operatively coupled to a respective Bragg fiber sensor (16) disposed on each catheter assembly (32). The wireless Bragg fiber relays (46) are configured to transmit radio frequency signals representative of the respective Bragg fiber sensor (16) outputs. During a procedure, data sensed along the fiber sensors (16) may be wirelessly transmitted from the individual wireless fiber relays (46) to a position determining system (30) having a compatible wireless signal receiver for receiving the wireless signal. The position determining system (30) may then analyze the fiber sensor data to calculate position information which can be communicated to the operator control system (22).

FIG. 6D is a side view of a single robotic arm (28) and surgical instrument assembly (46) from a da Vinci system, such as the da Vinci System (20) described above and shown in FIG. 6A. The instrument assembly (47) has a Bragg fiber sensor (16) disposed along at least part of its length, and a sensor cable (48) connected to the Bragg fiber sensor (16). FIG. 6E shows, at an enlarged scale, a perspective view of a typical surgical instrument assembly (46) of a typical da Vinci system (20 or 40). The surgical instrument assembly (47) includes an elongate shaft (50) having a wrist-like mechanism or other end effector (52) located at a distal working end (54) of the shaft (50). A housing (56) is provided at the opposite end of the shaft (50), which is configured to detachably couple the proximal end (58) of the instrument assembly (47) to the robotic arm (28). A Bragg fiber sensor (16) is provided within the shaft (50) and extends from the distal working end (54) back to the housing (56). As the instrument assembly (47) is manipulated and travels on the robotic arm (28), movements may be sensed by the fiber sensor (16) and such data communicated to a computer, such as the position determining system (30) or an integrated operator control system (22) for analysis and position determination.

FIG. 6F illustrates another embodiment of a da Vinci-like patient-side telesurgical system (60) in an exemplary operating room installation having a patient table (64) and a patient (15). In this example, the telesurgical system (60) has four robotic arms (28) and a ceiling mount (62) for each robotic arm (28) mounted to the ceiling. Each of the arms (28) is equipped with a Bragg fiber sensor (16) which is operatively coupled to a wireless Bragg fiber relay (46). An instrument assembly (46) is operatively coupled to the arms (28). In operation, data is collected by the fiber sensors (16) as to instrument assembly (46) and arm (28) movements and wirelessly communicated to the position determining system (30).

Referring to FIGS. 6G-6L, various embodiments of a multi-link instrument system operably coupled to fiber Bragg sensors, a fiber Bragg sensing system, and a robotic instrument controller are depicted to illustrate various ways in which fiber Bragg sensing may be utilized to assist in the navigation and control of an instrument configuration such as that depicted in FIGS. 6G-6L. Referring to FIG. 6G, a flexible instrument (204) is depicted movably coupled to a first movable structural member (206), which is rotatably coupled to a second movable structural member (208), which is rotatably coupled to a third movable structural member (210), which is rotatably coupled to a mounting structure (200). The depicted joints (207) may be conventional hinge type joints, 3-degree-of-freedom ball and socket type joints, or other types of couplings suitable for suspending medical instruments. The linkage comprising the various members (206, 208, 210) is for illustration purposes, and it will be apparent to one skilled in the art that the same ideas described herein are applicable to less extensive linkages or structures. As shown in FIG. 6G, a single fiber Bragg sensor (16) may be operably coupled to the entire length of the flexible instrument (204) and associated supporting linkage (206, 208, 210), and operably coupled to a fiber Bragg sensing system (30), which is coupled to a robotic instrument controller (202), which may be operably coupled, via a communication link (216) such as an electrical cable, to the actuators, brakes, or the like which are configured to control physical movement of various aspects of the flexible instrument (204) and associated supporting linkage (206, 208, 210). With such a configuration, a single core or multi-core fiber Bragg sensor (16) may be utilized to provide precision feedback to the robotic instrument controller regarding where the entire flexible instrument (204) and associated supporting linkage (206, 208, 210) are in space relative to each other, and relative to a ground position or the mounting structure (200). At the junction between the mounting structure (200) and the most proximal structural member (210), the sterile barrier preferably is configured to accommodate a direct crossing of the fiber Bragg sensor (16) via a hole or similar adaptation. Referring to FIG. 6H, an embodiment similar to that of FIG. 6G is depicted, with the exception that an additional fiber Bragg sensor (220) is coupled to the instrument complex along the supporting linkage (206, 208, 210). This additional sensor (220) may be configured to provide additional data for common mode rejection purposes, or may be configured to facilitate monitoring of the position of the supporting linkage (206, 208, 210) so that the first fiber Bragg sensor (16) may have Bragg gratings concentrated more densely only at the portions of the instrument linkage distal to the distal termination of the second fiber Bragg sensor (220), in the depicted example along the length of the flexible medical instrument (204), for which it may be desirable to have more resolution of spatial movement feedback to the robotic instrument controller (202). FIG. 6I depicts a similar configuration. FIG. 6J depicts an embodiment similar to that of FIGS. 6H and 6I, with the exception that a third fiber Bragg sensor (222) is included to provide additional redundancy for common mode error rejection, or further distributed monitoring of the rotational or strain-based deflections of the various structures to which the fiber Bragg sensors are operably coupled. For example, in one embodiment, the first sensor (16) may be configured to provide high-resolution monitoring of the flexible instrument (204) only by having a high density of Bragg gratings along this associated portion of the fiber Bragg sensor (16), the second sensor (220) may be configured to monitor relative positioning of the first structural member (206) relative to the second (208), and the second (208) relative to the third (210), which the third sensor (222) may be configured to monitor relative positioning of the second structural member (208) relative to the third (210), for common mode rejection analysis using the data from the second sensor (220) in re that mechanical association, as well as relative positioning of the third structural member (210) relative to the mounting structure (220) or ground position. Further, each of the three sensors (16, 220, 222) may be configured to monitor positioning along their entire length. As discussed above, FIG. 6K depicts an embodiment configured to wirelessly transmit data from the sensors (16, 220) to the fiber Bragg sensing system (30) via antennae (228) to avoid fiber crossings of the sterile barrier (214). FIG. 6L depicts an embodiment similar to that of FIG. 6G, with the exception that the fiber Bragg sensor (16) is positioned approximately along the central axis of each structural member (206, 208, 210) and joint (207). Another aspect of the embodiment of FIG. 6L is a slack portion (230) of the fiber Bragg sensor (16) to facilitate relative motion of the flexible instrument (204) relative to the first structural member (206).

Another surgical system that can benefit from accurate position information is the NIOBE Magnetic Navigation System and associated Magnetic GentleTouch Catheters, all available from Stereotaxis, Inc. of St. Louis, Mo. Stereotaxis provides products for magnetically-assisted surgery. FIG. 7A is a perspective view of a system (70) for magnetically assisted surgery. The system (70) generally comprises two sections; a magnet assembly (72) and a patient support assembly (74). During a procedure, a patient (15) is located on the table (76) of the patient support assembly (74) and a catheter is inserted into the patient's body and navigated to the region of interest. By controlling the strength and orientation of the magnetic fields produced from the magnet assembly, a magnetic catheter can be remotely controlled in response to the varying magnetic fields. For example, by pivoting and rotating the magnet assembly and moving the patient assembly, the magnetic fields will cause the magnetic elements of a catheter located in the patient to respond to the changing fields. In one implementation, it is contemplated that one or more Bragg fiber cables are located along the elongated portions of each magnetic catheter. Thus as the magnetic catheter is manipulated and repositioned, changed may be detected along the optical fibers and communicated to a computer for position analysis and determination.

FIG. 7B illustrates a patient lying on the table (76) of the patient support assembly (74) and having a Stereotaxis magnetic catheter (78) including a Bragg fiber sensor (16) introduced into the patient's head. In this illustration, the region of interest is the brain (115) and thus the patient's head is located about the magnet assembly (72). FIGS. 7C-7E illustrate various embodiments of magnetic ablation catheters (80) having one or more Bragg fiber sensors (16). The magnetic catheters (80) include an outer elongate body (81) and an ablation catheter (82) located within. The ablation catheter (82) has one or more electrodes (84) for ablating tissue. The magnetic catheter (80) may further include a circumferential mapping catheter (86) having one or more electrodes (84) for mapping electrical signals from tissue such as heart tissue. The magnetic catheter (80), ablation catheter (82), and mapping catheter (86) can be magnetically navigated to an ablation site, such as left atrium, for example using the system (70). The ablation catheter (82) and mapping catheter (86) may each be disposed within an anchor member (88) configured so that the ablation catheter (82) or mapping catheter (86) may be retracted into the anchor member (88) during navigation to the ablation site, and then extended out of the anchor (88) when the site has been reached. The magnetic catheter (80), ablation catheter (82) and/or the mapping catheter (86) may each have one or more Bragg fiber sensors (16) disposed longitudinally along at least part of their structures. As the magnetic catheter (80) is navigated with a patient's body, the Bragg fiber sensors (16) sense data related to position changes and bending of the fibers. This telemetry is relayed back to the navigation system (such as a position determining system (30)) for analysis and position determination.

Another surgical system that may benefit from position information during a surgical procedure is the Mako Haptic Guidance System from Mako Surgical, Inc. of Ft. Lauderdale, Fla. Mako produces a robotic system for orthopedic surgical procedures. A haptic guidance system provides sensory feedback (e.g. tactile and/or visual and/or acoustic) to the operator to assist in performing a procedure. FIG. 8A illustrates one embodiment of a Mako haptic guidance surgical system (90) that utilizes method of position determination with one or more Bragg fiber sensors (16). The surgical system (90) includes a computer system (92), a haptically-enabled device (94), and a tracking (or localizing) system (96). In operation, the surgical system (90) enables comprehensive, intraoperative surgical planning. The surgical system (90) also provides haptic guidance to a user and/or limits the user's manipulation of the haptically-enabled device (94) as the user performs a surgical procedure. The computing system (92) includes hardware and software for operation and control of the surgical system. In this embodiment, the computer system (92) also analyzes data from the Bragg fiber sensor (16) to determine the position of the arm (98) of the haptically-enabled device (94) and a distal tool or end effector (100). In one implementation, a Bragg fiber sensor (16) is coupled to the arm (98) of the haptically-enabled device (94). At least one of the optical fibers of the Bragg fiber sensor (16) extends to all the way to the distal working end of the arm (98) having the end effector (100). As the arm (94) moves during a surgical procedure and the end effector (100) is manipulated on a patient, the movements are sensed by the fiber sensor (16) and communicated to the computer system (92). The computer system (92) may be configured to process the data from the fiber sensor (16) to determine the position and orientation of the arm (94) and/or the end effector (100). By analyzing this data, an operator at the computer system (92) may accurately know the location and orientation of the end effector (100) and the haptic arm (98).

FIG. 8B illustrates one embodiment of a Mako haptic robot (94) comprising a base (102), an arm (98), an end effector (100), a user interface (104), and a Bragg sensor fiber (16). The base (102) provides a foundation for the haptically-enabled device (94). The arm (98) is disposed on the base (102) and is adapted to enable the haptically-enabled device (94) to be manipulated by the user. The arm (102) may be any suitable mechanical or electromechanical structure but is preferably an articulated arm having four or more degrees of freedom (or axes of movement), such as, for example, a robotic arm known as the “Whole-Arm Manipulator” currently manufactured by Barrett Technology, Inc. The Bragg fiber sensor assembly of this example includes a Bragg sensor fiber (16) extending from a sensor module (106), along the entire length of the robotic arm (98) all the way to the tip of the end effector (100). In alternative embodiments, a plurality of fiber sensors (16) may be employed to different segments along the arm (98). The sensor module (106) of this illustration collects all the sensed data and communicates the data to the computer system (92) via a cable or wirelessly. In another implementation, the sensor module (106) may be configured to analyze the data from the fiber sensors (16) and then simply communicate the position data directly to the computer system (92).

Yet another surgical system that can use accurate position information is the CyberKnife robotic radiosurgery system manufactured by Accuray Inc. of Sunnyvale, Calif. The CyberKnife system provided therapeutic treatment to moving target regions in a patient's anatomy by creating radiosurgical lesions. The technique includes determining a pulsating motion of a patient separately from determining a respiratory motion, and directing a radiosurgical beam, from a radiosurgical beam source, to a target in the patient based on the determination of the pulsating motion. Directing the radiosurgical beam to the target may include creating a lesion in the heart to inhibit atrial fibrillation. Due to the nature of the treatment and the radiation involved, it is desirable to have accurate positioning of the target sites. For example, the system may have to take into account the respiratory motion of the patient, and compensate for movement of the target due to the respiratory motion and the pulsating motion of the patient.

FIG. 9A illustrates one embodiment of a radiosurgery system, such as the CyberKnife, employing a Bragg fiber position sensing scheme. The system (110) includes an Accuray radiosurgical beaming apparatus (112), a positioning system (114), an imaging device (116), and a controller (118). The system (110) may also include an operator control console (120) and display (122). The radiosurgical beaming apparatus (112) generates, when activated, a collimated radiosurgical beam (consisting of x-rays, for example). The cumulative effect of the radiosurgical beam, when directed to the target, is to necrotize or to create a lesion in a target within the patient's anatomy. By way of example, the positioning system (114) is an industrial robot, which moves in response to command signals from the controller (118). The beaming apparatus (112) may be a small x-ray linac mounted to an arm of the industrial robot. In this illustration, one or more Bragg fiber sensor(s) (16) are attached to the robot arm (124) and the beaming apparatus (112). As the robot moves the arm (124) and the beaming apparatus (112) over the patient, the fiber sensor(s) (16) provide indications of the position movements to a computer system (126). By analyzing the sensed data from the fiber sensor(s) 16, an accurate position of the arm and the beaming apparatus can be determined. By knowing these locations, the radiosurgical beam can be accurately aimed from the beaming apparatus (112) to the patient. FIG. 9B illustrates the distal portion of the Accuray robot arm (124) to which the beaming apparatus (112) is mounted. Also shown is the Bragg fiber sensor (16) extending along the exterior of the beaming apparatus (112) and the robot arm (124).

From the discussions thus far, the fiberoptic Bragg grating position determining method and apparatus has been employed in the context of robotic surgical systems and/or their associated catheter devices or beaming devices. It is also contemplated that the position determination techniques using Bragg fibers may also be employed with endoscopic instruments and endoscopic medical procedures. For example, one or more Bragg fiber sensors may be built into or located within a steerable endoscope device such as that produced by NeoGuide Systems Inc. of Los Gatos, Calif. FIG. 10A shows one variation of a steerable endoscope (130) which may be utilized for accessing various regions within the body without impinging upon the anatomy of the patient. The endoscope (130) generally has an elongate body (132) with a manually or selectively steerable distal portion (134) and an automatically controlled proximal portion (136). The elongate body (132) of the endoscope (130) is highly flexible so that it is able to bend around small diameter curves without buckling or kinking. A handle (138) at the proximal end of the elongate body may be connected to a steering control (142) which may be configured to allow a user to selectively steer or bend the selectively steerable distal portion of the elongate body in the desired direction. In one embodiment, an axial motion transducer (144) may be provided to measure the axial motion of the elongate body (132) as it is advanced and withdrawn. The Bragg fiber techniques of the present invention presents an alternative or additional means of position determination for this endoscope (132). As shown in FIG. 10A, a Bragg fiber sensor (16) extends from the distal end (134) of the elongate body (132) for a NeoGuide steerable endoscope (130) to the proximal end (136) and to a position determination module (140). The position determination module analyzes the data and may be configured to calculate the position of the distal tip (134) of the endoscope (130), various points along the elongate body (132), or even every point along the entire length of the endoscope (130). Because a steerable endoscope may take a tortuous route as it travels through the body, it is highly desirable to know the exact position of a portion of, or the entire, length of the endoscopic instrument, particularly if the elongate body takes many turns or circles about itself.

FIG. 10B illustrates a cross-sectional side view of a patient's head with a variation of a NeoGuide steerable endoscope (130) having a Bragg fiber sensor (16) disposed therethrough. FIG. 10C illustrates a cross-sectional anterior view of a heart (150) with a NeoGuide endoscopic device (130) having a Bragg fiber sensor (16) introduced via the superior vena cava and advanced to the right atrium.

FIGS. 10D-10F show examples of treating atrial fibrillation using an endoscopic device (130) that includes a Bragg fiber sensor (16). As shown in FIG. 10D, the distal portion (134) of endoscopic device (130) is advanced into the chest cavity through a port (152). The location and orientation of the portions of interest of the endoscopic device (130) are determined using the data received from the Bragg fiber sensor (16). Turning to FIGS. 10E and 10F, the distal portion (134) is advanced proximal the location(s) of the heart to be given treatment in order to treat the atrial fibrillation.

FIG. 10G illustrates another embodiment of an endoscope (130), in this case having a guide tube (154) wherein the endoscope (130) is slidably insertable within the lumen of a guide tube (154). In addition, the endoscope (130) is provided with an end effector (100). In this embodiment, the endoscope (130) and guide tube (154) have separate Bragg fiber sensors (16) such that the position of the endoscope (130) and guide tube (154) may be separately determined.

FIG. 10H illustrates a colonoscopy procedure wherein a NeoGuide steerable endoscope (130) with a Bragg sensor fiber (16) is advanced through a colon. The endoscope (130) may also include a guide tube (154), and separate Bragg fiber sensors (16) on the endoscope (130) and guide tube (154).

In the descriptions of the various embodiments of surgical systems equipped with one or more Bragg fiber sensors (also referred to as Bragg grating fibers) and associated position sensing instrumentation, the Bragg fiber sensor has been described as being disposed on, coupled to or located on a robotic arm, instrument, catheter, and/or tool. In addition, it is contemplated that in some embodiments, the Bragg fiber or fiber bundles may be mounted to or installed on the exterior surface or housing of the robotic instrument. For example, one or more Bragg grating fibers may be routed on the external housing of a robotic arm of the Intuitive Surgical da Vinci system, the Mako system, or the Accuray system. Similarly, one or more Bragg fibers may be fastened on the outer surface of the instrument of the Intuitive Surgical, Stereotaxis, or NeoGuide system or apparatus. Furthermore, a Bragg fiber may be attached to a tool instrument or end-effector which may be operably coupled with the distal end of an instrument.

It is further contemplated that in alternative embodiments, the Bragg fiber sensors may be installed within or integrated into the robotic instrument itself. For example, one or more Bragg fiber sensors may be routed internally to the robotic arm of the Intuitive Surgical da Vinci system, the Mako system, or the Accuray system. Similarly, one or more Bragg fiber sensors may be located within the catheter instrument of the Intuitive Surgical catheter, Stereotaxis catheter, or NeoGuide catheter. Furthermore, a Bragg fiber may be built into a tool instrument or end-effector at the distal end of a catheter instrument. Accordingly, as used herein, the term “disposed on” shall include without limitation all of these described methods of providing the described structure with a fiber sensor, and shall not be limited to any particular mounting method or location relative to the structure.

In the descriptions above, it has also been disclosed that position data sensing/analysis logic system (referred to generically as the “position determining system” or “sensor module”) may be located either separated from the robotic system or alternatively on the robotic system itself. In some embodiments, the position determining system may be integrated with the control system of the Intuitive Surgical/Mako/Accuray/NeoGuide/Stereotaxis surgical system. In other embodiments, the position determining system may be stand-alone or part of another computer system. Because of these different implementations, data communication between the Bragg fiber sensors, the position determining system, and/or the control system for the robotic device may be accomplished in a variety of ways. In the embodiments described above, the communication may be conducted via physical cables, wireless transmissions, infrared, optically, or other suitable means. Although the examples described herein are in the context of one Bragg fiber sensor or fiber bundle for clarity, it is contemplated that a plurality of optical fibers or fiber bundles may be deployed on each robotic arm, catheter, or tool device, thus providing additional position data and redundancy if so desired.

While multiple embodiments and variations of the invention have been disclosed and described herein, such disclosure is provided for purposes of illustration and not limitation. It will be apparent to those skilled in the art that many combinations and permutations of the disclosed embodiments are possible, for example, depending upon the medical application. Thus, the invention is to be limited only by the appended claims and their equivalents. 

1. A positionable medical instrument assembly, comprising: a first member; a second member coupled to the first member by a movable joint; and a Bragg sensor optical fiber coupled to the first and second members, such that relative movement of the first and second members about the movable joint causes a bending of at least a portion of the Bragg sensor optical fiber, the Bragg sensor optical fiber having a proximal end operatively coupled to a controller configured to receive signals from respective Bragg gratings on a fiber core of the Bragg sensor optical fiber indicative of a bending thereof, the controller configured to analyze the signals to determine a relative position of the first and second members about the movable joint.
 2. The instrument assembly of claim 1, wherein the movable joint allows for pivotal motion of the second member relative to the first member in a single plane, and wherein the determined relative position of the first and second members about the movable joint comprises an angular displacement of the second member relative to the first member.
 3. The instrument assembly of claim 1, wherein the movable joint allows for movement of the second member relative to the first member in at least three degrees of freedom.
 4. The instrument assembly of claim 1, wherein the assembly comprises a robotic instrument driver configured to maneuver an elongate medical instrument movably coupled to the second member.
 5. A positionable medical instrument assembly, comprising: a plurality of positionable members, including a first member coupled to a second member by a first movable joint, and a third member coupled to the second member by a second movable joint; and one or more Bragg sensor optical fibers, each coupled to at least two of the first, second and third members such that relative movement of the first and second members about the first movable joint causes a corresponding bending of at least one Bragg sensor optical fiber, and a relative movement of the second and third members about the second movable joint causes a corresponding bending of a same or different at least one Bragg sensor optical fiber, each of the one or more Bragg sensor optical fibers having a proximal end operatively coupled to a controller configured to receive signals therefrom indicative of a bending of one or more portions thereof, the controller configured to analyze the signals to determine a relative position of the first, second and third members about the respective first and second movable joints.
 6. The instrument assembly of claim 5, wherein the first movable joint allows for movement of the second member relative to the first member in at least three degrees of freedom, and wherein the second movable joint allows for movement of the third member relative to the second member in at least three degrees of freedom.
 7. The instrument assembly of claim 6, the one or more Bragg sensor optical fibers including a first Bragg sensor optical fiber coupled to the first, second and third members, such that relative movement of the first and second members about the first movable joint, and relative movement of the second and third members about the second movable joint causes a bending of at least first and second respective portions of the first Bragg sensor optical fiber, and wherein the controller is configured to analyze signals received from the first Bragg sensor optical fiber to determine a relative position of the first, second and third members about the respective first and second movable joints.
 8. The instrument assembly of claim 6, the one or more Bragg sensor optical fibers including a first Bragg sensor optical fiber coupled to the first and second members, such that relative movement of the first and second members about the first movable joint causes a bending of at least a portion of the first Bragg sensor optical fiber, and a second Bragg sensor optical fiber coupled to the second and third members, such that relative movement of the second and third members about the second movable joint causes a bending of at least a portion of the second Bragg sensor optical fiber, wherein the controller is configured to analyze respective signals received from the first and second Bragg sensor optical fibers to determine a relative position of the first, second and third members about the respective first and second movable joints.
 9. The instrument assembly of claim 5, further comprising an elongate medical instrument movably coupled to the second member.
 10. A positionable medical instrument assembly, comprising: a first member; a second member coupled to the first member by a movable joint; and a plurality of Bragg sensor optical fibers coupled to the first and second members, such that relative movement of the first and second members about the movable joint causes a bending of at least a portion of each of the Bragg sensor optical fibers, the Bragg sensor optical fibers having respective proximal ends operatively coupled to a controller configured to receive signals from respective Bragg gratings located on the Bragg sensor optical fibers and indicative of a respective bending thereof, the controller configured to analyze the signals to determine a relative position of the first and second members about the movable joint.
 11. The instrument assembly of claim 10, wherein the movable joint allows for pivotal motion of the second member relative to the first member in a single plane, and wherein the determined relative position of the first and second members about the movable joint comprises an angular displacement of the second member relative to the first member.
 12. The instrument assembly of claim 10, wherein the movable joint allows for movement of the second member relative to the first member in at least three degrees of freedom.
 13. The instrument assembly of claim 10, wherein the assembly comprises a robotic instrument driver configured to maneuver an elongate medical instrument movably coupled to the second member.
 14. A medical instrument system, comprising: an instrument driver; a sterile barrier; an elongate flexible instrument body operatively coupled to the instrument driver through the sterile barrier; a Bragg sensor optical fiber coupled to the elongate instrument body, such that relative bending of the instrument body causes a corresponding bending of at least a portion of the Bragg sensor optical fiber, the Bragg sensor optical fiber having a proximal end operatively coupled to a position sensor controller located on a sterile field side of the sterile barrier and configured to receive signals from respective Bragg gratings located on at least one fiber core of the Bragg sensor optical fiber and indicative of a bending thereof, the sensor controller configured to analyze the signals to determine a relative position of the instrument.
 15. The medical instrument system of claim 14, wherein the position sensor controller transmits wireless signals to an instrument driver controller located outside the sterile field to communicate to the instrument driver a relative position of the instrument. 